Water-soluble cellulose ether plasticized with a cyclomethylene sulfone



Patented May 24, 1949 UNITED V-ISTATES PATENT 1 WATER-SOLUBLE. oELLULosa'.ETHEn;PLAs-' 'rrcrznn WITH 'A oYoLoMETnYLEmrsUL- '1 George .W.Hooker,cSarni-a, Ontario, Canada, and ".--Norman E. Peterson, MidlandgsMichz,rassignors to TheDowGhemical Company, MifllahdaMlch a corporation of Delaware No Drawing. Applicationtluly 328%1945,

. Serial N01 607,664

10 I Claims. 1

lulose ether compositions containing them, and I are objectionable for this reason.

One use for which the Water-soluble: cellulose f ethers might be advantageously employed, be- 1 cause of their insensitiveness to hydrocarbons and other organic solvents, is in the inner linings of the self-sealing fuel cells (gasoline tanks) for military aircraft. For such use, however, it is necessary to provide a composition which can be bonded firmly to rubber, and which will form a continuous, flexible film. Such coatings cannotbeprepared-fromlthese cellulose ethers Without plasticizers,- and the .plasticizer: must remain "permanently in the-film. and must not exude therefrom.

It is accordingly among the objects of the present invention toeprovide a water-soluble cellulose ethermcomposition, vand. particularly a methyl cellulose compositiomwsuitable for the prepara- ..tion of flexible films,..and-containing substanwltially permanent,.nonrbleeding plasticizer. A related object is to providesuch a composition WhiCh'iS inert tovmotorfuel'and may be bonded .to rubber, as in"self-sealing fuel cells. Other .and. related objects, some of. which 'may. appear inthefollowing descriptionand claims, include L theiprovision ofa specific type of vplasticizer for water-soluble cellulose ethers, which does not bleed or evaporate. from .compositionscontaining 'it,"and which will give the desired flexibility. and

continuity to films of such compositions.

. We have now found that, in accordance with the present invention, the foregoing and related objects may be 'attained'through the prepara- 4 tionof amomposition of matter comprising a water-soluble cellulose "ether plasticized with "from 10 per cent-up tonthelimit of compatibility f 3,4-dehydro cyclotetramethylene sulfone, the r 3-methyl iderivativezthreof, cyclotetramethylene lgisulfonacand; thevfiemethyle; 3aalkoxyw, and 3''- a-methyl,4eatkoxmderivativesrota cyclotetramethylene sulfone, wherein .theyal-koxy-rgroupscontain from 1 to 8 carbon atoms, inclusive. The identity of the compounds concerned may be made clear by-reference to the-l-following structural -:formulas:

HC=CH iH2C--1-CH2 i4. 3L 1 (L4. 3i H2 2 H, i111 5 2 H2 r o o .1 0 o i3 lrdehydro-cyclotetra- Cyclotetramethylene s L-methylene sulfone ,m sulfone The :compositiqns:-.preferably comprise methyl celluloseand an alkoxy cyclortetramethylene sulfone wherein the ralkoxy radical containsfrom 6 to 8 carbon atoms, inclusive. Particularly desirable; -compositions comprise methyl cellulose and (ZT-ethyl hexyloxy)-cyclotetramethylene sulfone, since these :give films with excellent low :I temperature flexibility, which do notlose that flexibility after heating for two weeks at 110 C., and which are easily bonded torubber to give gasolin'eproof coatings.

Among the numerous'sulfones' which are avail- ..able; or, easily: produced, only; the: classes: abovedisclosedzhavazbeen'zfounid to: have the :desired "'iproperties rim; ompositions of the= water-soluble celluloselethersiraExamples oflcom-pounds falling :wwithin; the reeitedwolas es,egiyen purely by :way of: illustration; :are

(a) 3,4-dehydro-cyclotetramethylene sulfone '(b')'* Cyclotetramethylendsulf one (c) -3-- methyl,3;4-- dehydro-cyclotetramethylene sulfone (d) 3=methylr"cyclotetramethylene sulfone (6) 3-methoxy .cyclotetrainethylene sulfone 40 (if) 3- methyl,4"'- m'ethoxy cyclotetramethylene "sulfone (0)1 3-'ethoxy cyclotetramethylene sulfone (It) 3- (nebutyloxy:cyclotetramethylene sulfone '(i) :'3=(se c.1butyl oxy "cyclotetramethylenesulfone ('1' 3 (n-hexylo'xy) cyclotetramethylene. sulfone (k) 311 (2 jethylgbutyloxw" cyclotetramethylene sulfone (Z) 3- (nroctyloxy): loyclotetramethylene sulfone (m') 3f- (2 j-lethyl hexyloxy) ficyclotetrarnethylene sulfone .-It. should :heimoted thatlzin. thenmono-substitution products;oftcyclotetnamethylenesulfone; the sand-the 47'DOSi1iiOHS arerequivalentw; The abovea-ahstedrand:relatedecompounds :maybe: prepared serironrt' .butadiene: or-r zvdseprene, wwhich --form un- 3 saturated sulfones with sulfur dioxide. These unsaturated sulfones may be reduced to form saturated compounds, or they may be caused to react with alcohols to form the alkoxy compounds of the types listed.

The compositions may be prepared by adding a water solution of the sulfones to an aqueous solution of the water-soluble cellulose ether. The solutions are preferably quite concentrated, to minimize the amount of drying required to produce a film after the solution has been cast on a smooth surface.

To illustrate the practice of the invention, the following table presents data regarding the tensile strength and elongation of films of compositions containing various of the sulfones identi fied by the same index letter as is employed in the foregoing list. Two types of methyl cellulose were employed, so the table is divided into two parts, for comparison between the plasticized compositions and the corresponding unthe gasoline and. the sensitive rubber. Coatings on paper, cloth, wood, metal or other surfaces may be subjected to temperatures up to or somewhat above 100 C. for considerable periods of time without adversely affecting the flexibility or the hydrocarbon resistance of the coatings.

For most purposes it is preferred to employ at least 10 per cent of the sulfone in the methyl cellulose composition, and any greater quantity may be used, up to the limit of compatability. As the quantity of plasticizer is increased, the composition generally becomes softer, as shown in the table, but not excessively so. Thus, a good clear film was prepared from 33 per cent of methyl cellulose and 67 per cent of 3- methoxy cyclotetramethylene sulfone. This film had a tensile strength of about 300 kilo grams per square centimeter and remained strong and fiexible and clear after storage in air at prevailing room temperature for over 3 modified methyl cellulose. years.

Table Air dried Baked 2 wks. at 110 0.

Pl t Amount,

as icizer per cen by wt. 232i Elongation, aig g Elongation,

KgJsq. cln. per cent Kg./sq. 0111. per cent Blank (1).... 0 705 27 683 (a) crude. 30 530 37 627 (a) refined... 485 37 583 30 (c) 15 890 45 707 20 30 620 41 750 20 30 410 48 590 15 15 583 730 28 30 323 480 13 15 466 35 592 25 30 418 40 551 15 0 7 10 695 15 15 625 22 565 12 30 340 28 555 22 15 630 22 560 12 30 335 28 555 22 30 310 13 520 17 15 475 15 535 14 30 420 20 505 20 30 435 19 505 25 15 530 20 640 22 30 475 16 525 24 Similar results were obtained using other sulfones falling within the previously defined group, instead of the ones specifically listed in the table.

The substitution of carboxymethyl cellulose of the sulfones reported effectively plasticize methyl cellulose films containing them, and that the plasticizing action persists to the greatest extent in baked films containing various hexyloxy and octyloxy cyclotetramethylene sulfones. The elongation values of films containing 3-(2-ethyl butyloxy)- and 3-(2-ethyl hexyloxy)-cyclotetramethylene sulfones are actually higher after the film has been heated for two weeks at 110 C. than when the film was simply air dried. All tensile and elongation tests Were made on films conditioned for one week at F. and 50 per cent relative humidity.

The compositions here concerned are all inert to the action of petroleum hydrocarbons of the types present in aviation gasoline. Coatings of the new compositions may be applied from aqueous solution to the surface of the rubber lining of self-sealing gasoline tanks, or to a textile fabric which is to be sealed to such a rubber lining, and form a permanent barrier between When methyl cellulose films containing the herein recited plasticizers are compared with others containing glycerol or diethylene glycol, it is found that the new compositions give films of greater clarity and a noticeable absence of spewing, while the compositions containing the polyhydric alcohol plasticizers exude or spewthe plasticizer, and gradually become deplasticized.

In addition to the uses heretofore suggested for the new compositions, they may be employed as flexible greaseproof coatings for paper used in wrapping foods for freezing or for wrapping meats, fats and cheese. The compositions may not only be employed for many purposes for which the usual glycerol plasticized compositions are unsatisfactory, but also may be substituted for those prior compositions in most of the established uses for the Walter-soluble cellulose ethers.

We claim:

1. A composition of matter consisting of a water-soluble cellulose ether, and from 10 per cent to about 6'7 per cent of a compound selected from the group consisting of 3,4-dehydro-cyclotetramethylene sulfone, the 3-methyl derivative thereof, cyclotetramethylene sulfone, and the 3- methyl-, 3-alkoxy-, and 3-methyl,4-alkoxy derivatives of cyclotetramethylene sulfone, wherein the alkoxy groups contain from 1 to 8 carbon atoms, inclusive.

2. A composition of matter consisting of a water-soluble cellulose ether, and from per cent to about 67 per cent of a 3-alkoxy-cyclotetramethylene sulfone wherein the alkoxy groups contain from 1 to 8 carbon atoms, inclusive.

3. A composition of matter consisting of a water-soluble cellulose ether, and from 10 per cent to about 67 per cent of a 3-alkoxy-cyclotetramethylene sulfone wherein the alkoxy groups contain from 6 to 8 carbon atoms, inclusive.

4. A composition of matter consisting of a water-soluble cellulose ether, and from 10 per cent to about 30 per cent of 3-(2-ethy1 butyloxy) cyclotetramethylene sulfone.

5. A composition of matter consisting of a water-soluble cellulose ether, and from 10 per cent to about 30 per cent of 3-(2-ethyl hexyloxy) cyclotetramethylene sulfone.

6. A composition of matter consisting of a water-soluble methyl cellulose, and from 10 per cent to about 6'7 per cent of a compound selected from the group consisting of 3,4-dehydro-cyclotetramethylene sulfone, the B-methyl derivative thereof, cyclotetramethylene sulfone, and the 3- methyl-, 3-alkoxy-, and 3-methyl,4-alkoxy derivatives of cyclotetramethylene sulfone, wherein the alkoxy groups contain from 1 to 8 carbon atoms, inclusive.

7. A composition of matter consisting of a water-soluble methyl cellulose, and from 10 per cent to about 67 per cent of a. 3-alkoxy-cyclotetramethylene sulfone wherein the alkoxy groups contain from 1 to 8 carbon atoms, inclusive.

8. A composition of matter consisting of a Water-soluble methyl cellulose, and from 10 per cent to about 67 per cent of a 3-alkoxy-cyc1otetramethylene sulfone wherein the alkoxy groups contain from 6 to 8 carbon atoms, inclusive.

9. A composition of matter consisting of a water-soluble methyl cellulose, and from 10 per cent to about 30 per cent of 3-(2-ethylbuty1oxy)- cyclotetramethyiene sulfone.

10. A composition of matter consisting of a water-soluble methyl cellulose, and from 10 per cent to about 30 per cent of 3-(2-ethyl hexyloxy) cyclotetramethylene sulfone.

GEORGE W. HOOKER.

NORMAN R. PETERSON.

REFERENCES CITED UNITED STATES PATENTS Name Date Hofiman et a1 June 19, 1945 Number 

